Study of Flow and Thermal Evolution in Zinc Bath During Galvanisation Using a 3D CFD Model

Galvanisation, the coating of zinc on steel sheets, can increase the corrosion resistance of steel. For this purpose, the steel sheets from the furnace, after continuous casting, are passed through a molten zinc bath with the help of rollers. This is called a continuous galvanising bath. This process provides a surface finish almost similar to electroplating. While analysing the complex convection pattern during galvanisation, the convection current can be divided into forced and natural convection. The forced convection is due to strip movement and natural convection is due to temperature gradient. The heater (inductor), required for keeping the zinc in a molten state, also plays a significant role in flow patterns due to magnetic Lorentz force and Joule heating. The effect of strip velocity, natural convection, dross particle formation, ingot addition and inductor aspects have been studied in this paper. Based on the study, the chances of formation of dross particles in different regions of the zinc bath have been predicted. Also, a parametric study of strip angle and inductor power has been presented in the paper.